The present proposal is to continue an on-going program on the purification of human urinary erythropoietin. Crude human urinary erythropoietin provided by the National Heart, Lung and Blood Institute will be purified to a level upwards of 10,000 units/mg utilizing purification techniques on-going in the laboratories of Pharmacology and Biochemistry at Tulane University. The techniques to be used for purification are a modification of those described in the original application and involves the use of heat treatment, solubilization techniques, affinity chromatography using immobilized wheat germ lectin, phenol-PAS treatment, ethanol fractionation, Sephadex G-100, hydroxyl apatite, and preparative electrophoresis and isotachophoresis. The exhypoxic polycythemic mouse assay (Fe59 incorporation in red cells) will be used to monitor the eluates and fractions at each step in the purification scheme. Determination of molecular weight, amino acid composition and identification of the sugar residues will also be carried out on the ultra purified erythropoietin preparation when it reaches homogeneity. The purified erythropoietin will be sent to the Blood Resources Divison of the National Heart, Lung and Blook Institute for disposition.